Research and development on a tunneling magnetoresistive (TMR) element using “a magnetoresistive effect” in which electrical resistance changes in response to a magnetic field are being conducted in the field of MRAM (magnetoresistive random access memory), a magnetic sensor, or the like. The tunneling magnetoresistive element has a configuration in which an insulating layer (tunnel barrier layer) is sandwiched between two magnetic layers, and a current between the magnetic layers (tunneling current) varies depending on the difference in the magnetization directions of the magnetic layers.
The tunneling magnetoresistive element in which the magnetization directions of the magnetic layers are perpendicular to the lamination direction is called “in-plane magnetization-type”, and the tunneling magnetoresistive element in which the magnetization directions of the magnetic layers are the same as the lamination direction is called “perpendicular magnetization-type.” The perpendicular magnetization-type tunneling magnetoresistive element has advantages such as possible size reduction of the element, high thermal disturbance resistance, and a small magnetization inversion current, as compared with the in-plane magnetization-type tunneling magnetoresistive element. However, because the properties of the element significantly differ depending on the material of each layer, crystallinity, or the like, a configuration of the element having more excellent properties is being searched for.
In particular, an element having a configuration in which a magnetic layer includes CoFeB (cobalt iron boron) material (CoFeB, CoFeBP, and the like), and an insulating layer includes MgO (magnesium oxide) is investigated as a perpendicular magnetization-type tunneling magnetoresistive element having excellent properties. For example, Patent Document 1 describes a perpendicular magnetization-type MTJ (Magnetic Tunnel Junction) element in which an interface fixed layer includes a CoFeB alloy, and a tunnel barrier layer includes MgO. In this element, the tunnel barrier layer including MgO is deposited on the interface fixed layer including a CoFeB alloy. Accordingly, it is possible to improve the crystallinity of MgO, and to produce an element having a high MR (Magnetic Resistance) ratio and high spin injection efficiency.